American Prometheus (48 page)

On the other hand, I remember quite clearly the impression it made on me when, at the beginning of the conversation, you told me without preparation that you were certain that the war, if it lasted long enough, would be decided with atomic weapons. I did not respond to this at all, but as you perhaps regarded this as an expression of doubt, you related how in the preceding years you had devoted yourself almost exclusively to the question and were quite certain that it could be done, but you gave no hint about efforts on the part of German scientists to prevent such a development.

What was said or not said between Bohr and Heisenberg remains a source of considerable controversy. Oppenheimer himself later wrote, cryptically: “Bohr had the impression that they [Heisenberg and his colleague Carl Friedrich von Weizsäcker] came less to tell what they knew than to see if Bohr knew anything that they did not. I believe that it was a standoff.”

One thing is clear, however: Bohr came away from the encounter with a great fear that the Germans might end the war with an atomic weapon. In New Mexico, he conveyed this fear to Oppenheimer and his team of scientists. Not only did he tell them that Heisenberg had confirmed the existence of a German bomb project, Bohr also displayed a drawing of what he said was a bomb, allegedly sketched by Heisenberg himself. One glance, however, persuaded everyone that the sketch depicted, not a bomb, but a uranium reactor. “My God,” Bethe said when he saw the drawing, “the Germans are trying to throw a reactor at London.” If it was disquieting to learn that the Germans were indeed working on a bomb project, it was reassuring that they seemed to be pursuing a highly impractical design. After discussion of the issue, even Bohr was persuaded that such a “bomb” would fizzle. The next day, Oppenheimer wrote Groves to explain that an exploding uranium pile would actually “be a quite useless military weapon.”

OPPENHEIMER ONCE observed that “it is easy, as history has shown, for even wise men not to know what Bohr was talking about.” Like Bohr, Oppenheimer was never simple or straightforward. At Los Alamos, the two men sometimes seemed to be mimicking each other. “Bohr at Los Alamos was marvelous,” Oppenheimer later wrote. “He took a very lively technical interest. But his real function, I think, for almost all of us, was not the technical one.” Instead, Bohr came “most secretly of all,” as Oppenheimer explained, to advance a political cause—the case for openness in science as well as international relations, the only hope to forestall a postwar nuclear arms race. This was a message Oppenheimer was ready to hear. For nearly two years, he had been preoccupied with complex administrative responsibilities. As the months rolled by, he was becoming less and less a theoretical physicist and more and more a science administrator. This transformation had to be intellectually stifling for him. So when Bohr showed up on the mesa speaking in deeply philosophical terms about the project’s implications for humanity, Oppenheimer felt rejuvenated. He assured Groves that Bohr’s presence had greatly helped morale. Up until then, Oppenheimer later wrote, the work “often looked so macabre.” Bohr soon “made the enterprise seem hopeful, when many were not free of misgiving.” He spoke contemptuously of Hitler and underscored the role scientists could play in his defeat. “His own high hope that the outcome would be good, that the objectivity, the cooperation of the sciences would play a helpful part, we all wanted to believe.”

Victor Weisskopf recalled Bohr telling him that “this bomb may be a terrible thing, but it might also be the ‘Great Hope.’ ” Early that spring, Bohr attempted to put his concerns on paper, drafting and redrafting a memorandum and then sharing it with Oppenheimer. By April 2, 1944, he had a draft that contained several basic insights. No matter how things ultimately worked out, Bohr argued, “it is already evident that we are presented with one of the greatest triumphs of science and technique, destined deeply to influence the future of mankind.” In the very near term, “a weapon of an unparalleled power is being created which will completely change all future conditions of warfare.” That was the good news. The bad news was equally clear, and prophetic: “Unless, indeed, some agreement about the control of the use of the new active materials can be obtained in due time, any temporary advantage, however great, may be outweighed by a perpetual menace to human security.”

In Bohr’s mind, the atomic bomb was already a fact—and control over this menace to humanity required “a new approach to the problem of international relationship. . . .” In the coming atomic era, humanity would not be safe unless secrecy was banished. The “open world” Bohr imagined was not a utopian dream. This new world already existed in the multinational communities of science. In a very pragmatic sense, Bohr believed the laboratories in Copenhagen, Cavendish and elsewhere were practical models for this new world. International control of atomic energy was only possible in an “open world” based on the values of science. For Bohr, it was the communitarian culture of scientific inquiry that produced progress, rationality and even peace. “Knowledge is itself the basis of civilization,” he wrote, “[but] any widening of the borders of our knowledge imposes an increased responsibility on individuals and nations through the possibilities it gives for shaping the conditions of human life.” It followed that in the postwar world each nation had to feel confident that no potential enemy was stock-piling atomic weapons. That would only be possible in an “open world” where international inspectors had full access to any military and industrial complexes and full information about new scientific discoveries.

Finally, Bohr concluded that such a sweeping new regime of international control could be inaugurated after the war only by promptly inviting the Soviet Union’s participation in postwar atomic energy planning— before the bomb was a reality and before the war was over. A postwar nuclear arms race could be prevented, Bohr believed, if Stalin was informed of the existence of the Manhattan Project and assured that it posed no threat to the Soviet Union. An early agreement among the wartime allies for the postwar international control of atomic energy was the only alternative to a nuclear-armed world. Oppenheimer agreed—indeed, he had shocked his security officers the previous August when he told Colonel Pash that he would “feel friendly” to the idea of the president informing the Russians about the bomb project.

It was easy to see the effect Bohr had on Oppenheimer. “[He] knew Bohr from way back and they were pretty close personally,” said Weisskopf. “Bohr was the one who really discussed these political and ethical problems with Oppenheimer, and probably that was the time [early 1944] when he began to think seriously about it.” One afternoon that winter, Oppenheimer and David Hawkins were walking Bohr back to his guest quarters in Fuller Lodge when Bohr playfully insisted on testing the thickness of the ice on Ashley Pond. The usually daring Oppenheimer afterwards turned to Hawkins and exclaimed, “My God, suppose he should slip? Suppose he should fall through? What would we all do then?”

The very next day, Oppenheimer beckoned Hawkins into his office, pulled a folder from his secure file cabinet, and let him read a letter Bohr had written to Franklin Roosevelt. Oppie obviously set great store by the precious document. According to Hawkins, “the implication was that Roosevelt had fully understood. And this was a great source of joy and optimism. . . . It’s interesting. We all lived under this illusion, you see, for the rest of the time at Los Alamos, that Roosevelt had understood.”

BOHR HAD long since converted his particular “Copenhagen” interpretation of quantum physics into a philosophical world view that he named “Complementarity.” Bohr was forever trying to take his insights into the physical nature of the world and apply them to human relations. As the historian of science Jeremy Bernstein later wrote: “Bohr was not satisfied to limit the idea of complementarity to physics. He saw it everywhere: instinct and reason, free will, love and justice, and on and on.” He quite understandably saw it in the work at Los Alamos too. Everything about the project was fraught with contradictions. They were building a weapon of mass destruction that would defeat fascism and end all wars—but also make it possible to end all civilization. Oppenheimer quite naturally found it comforting to be told by Bohr that the contradictions in life were nevertheless all of a piece—and therefore complementary.

Oppenheimer so admired Bohr that in years to come he often took it upon himself to translate him to the rest of humanity. Not many understood what Bohr meant by an “open world.” And those who did were sometimes positively alarmed by the audacity of what Bohr was proposing. In the early spring of 1944, Bohr received a letter, long delayed in the mails, from one of his former students, the Russian physicist Peter Kapitza. Writing from Moscow, Kapitza warmly invited Bohr to come settle there, “where everything will be done to give you and your family a shelter and where we now have all the necessary conditions for carrying on scientific work.” Kapitza then passed on the greetings of a number of Russian physicists whom Bohr knew—broadly suggesting that they would all be delighted to have him join them in their “scientific work.” Bohr thought this a splendid opportunity, and he actually hoped that Roosevelt and Churchill would authorize him to accept Kapitza’s invitation. As Oppenheimer later explained it to his colleagues, Bohr wished “to propose to the rulers of Russia, who were then our Allies, via these scientists, that the United States and the United Kingdom ‘trade’ their atomic knowledge for an open world . . . that we propose to the Russians that atomic knowledge would be shared with them if they would agree to open Russia and make it an open country and part of an open world.”

To Bohr’s thinking, secrecy was dangerous. Knowing Kapitza and other Russian physicists, Bohr thought them perfectly capable of grasping the military implications of fission. In fact, he surmised from Kapitza’s letter that the Soviets already did know something about the British-American atomic program—and he thought it would only sow dangerous suspicions if the Russians concluded that the new weapon was being developed without them. Other physicists at Los Alamos agreed. Robert Wilson later recalled “bugging” Oppenheimer about why British scientists, but no Russian scientists, were working at Los Alamos. “It seemed to me that down the line,” Wilson said, “that was going to make for some very hard feelings.” By the war’s end, it is clear that Oppenheimer agreed, but during the war, he was circumspect, knowing that he was under constant surveillance, and so he always refused to be drawn into such conversations. Either he wouldn’t answer at all or he’d mutter that it wasn’t the business of the scientists to determine such things. “I don’t know,” Wilson later said, “I felt that perhaps he thought that I was testing him.”

Not surprisingly, Bohr’s attitude was not shared by the generals and politicians who employed the scientists. General Groves, for instance, never really thought of the Russians as allies. In 1954, he told the Atomic Energy Commission’s hearing board that “there was never from about two weeks from the time I took charge of this project any illusion on my part but that Russia was our enemy and that the project was conducted on that basis. I didn’t go along with the attitude of the country as a whole that Russia was a gallant ally.” Winston Churchill had a similar view of the Soviets, and he was outraged to learn of the Kapitza-Bohr correspondence from British intelligence. “How did he [Bohr] come into this business?” Churchill exclaimed to his science adviser, Lord Cherwell. “It seems to me Bohr ought to be confined or at any rate made to see that he is very near the edge of mortal crimes.”

Despite personal meetings with both Roosevelt and Churchill in the spring and summer of 1944, Bohr failed to persuade either leader that the Anglo-American monopoly in atomic matters was shortsighted. Groves later told Oppenheimer that he thought Bohr “was at times a thorn in the sides of everyone dealing with him, possibly because of his great mental capacity.” Ironically, as his influence with such political leaders waned, Bohr’s stature among the physicists at Los Alamos rose to new heights. Once again, Bohr was God and Oppie was his prophet.

BOHR HAD come to Los Alamos in December 1943 alarmed by what he had learned from his encounter with Heisenberg about the potential for a German bomb. He left Los Alamos that spring persuaded by intelligence reports that the Germans probably did not have a viable bomb program: “. . . from leakage regarding the activities of German scientists,” he noted, “it is practically certain that no substantial progress has been achieved by the Axis Powers.” If Bohr was convinced, then Oppenheimer too must have realized that the German physicists were in all likelihood far behind in the race to build a bomb. According to David Hawkins, Oppenheimer was told by General Groves at the end of 1943 that a German source had recently claimed that the Germans had abandoned their early bomb program. Groves suggested that it was hard to evaluate such a report; the German source might be passing on disinformation. Oppenheimer just shrugged. Hawkins recalled thinking to himself that it was too late—the men at Los Alamos “were committed to building a bomb regardless of German progress.”

CHAPTER TWENTY-ONE

“The Impact of the
Gadget on Civilization”

My feeling about Oppenheimer was, at that time, that this
was a man who is angelic, true and honest and he could do
no wrong. . . . I believed in him.

ROBERT WILSON

EVERYONE SENSED OPPIE’S PRESENCE. He drove himself around The Hill in an Army jeep or in his own large black Buick, dropping in unannounced on one of the laboratory’s scattered offices. Usually he’d sit in the back of the room, chain-smoking and listening quietly to the discussion. His mere presence seemed to galvanize people to greater efforts. “Vicki” Weisskopf marveled at how often Oppie seemed to be physically present at each new breakthrough in the project. “He was present in the laboratory or in the seminar room when a new effect was measured, when a new idea was conceived. It was not that he contributed so many ideas or suggestions; he did so sometimes, but his main influence came from his continuous and intense presence, which produced a sense of direct participation in all of us.” Hans Bethe recalled the day Oppie dropped in to a session on metallurgy and listened to an inconclusive debate over what type of refractory container should be used for melting plutonium. After listening to the argument, Oppie summed up the discussion. He didn’t directly propose a solution, but by the time he left the room the right answer was clear to all.